# Refractory Disseminated Intravascular Coagulation Caused by Endovascular Invasion of Squamous Cell Carcinoma of the Lung: A Case Report

## TL;DR

A 78-year-old man with lung cancer developed fatal, uncontrollable blood clotting due to cancer cells invading blood vessels.

## Contribution

This is the first reported case of uncontrollable DIC caused by lung cancer invading the endothelium.

## Key findings

- DIC was caused by intravascular invasion of squamous cell carcinoma along the pulmonary artery endothelium.
- Cancer cells, platelets, and leukocytes contributed to persistent clotting by attaching to endothelial cells.
- Autopsy confirmed tumor embolism and massive pulmonary embolism as underlying causes.

## Abstract

Disseminated intravascular coagulation (DIC) is a systemic intravascular activation of coagulation caused by various underlying conditions. Severe DIC cases could be fatal. We present a 78-year-old Japanese man who developed uncontrollable DIC, finally diagnosed as lung cancer and intravascular invasion along the endothelium of the pulmonary artery, massive pulmonary embolism, and tumor embolism in autopsy. Leucocytes, platelets, and cancer cells play roles in uncontrollable DIC by assisting the attachment of cancer cells to endothelia. Endothelium damage enhances coagulation and suppresses fibrinolysis. This is the first case of uncontrollable DIC caused by intravascular invasion of lung cancer along the endothelium.